Scientists Propose Redefining Planets To Include Pluto And Over 100 Celestial Bodies


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Solar System with eight planets and one dwarf planet (Photo Credit:

In 2006, the International Astronomical Union (IAU), which promotes and safeguards the science of astronomy, passed a resolution that classified all bodies (except satellites) in our solar system into three distinct categories – planets, dwarf planets, and Small Solar System Bodies. To qualify as a planet, the body had to orbit around the sun, have sufficient mass for its self-gravity to pull it into a round shape, and have cleared the neighborhood around its orbit. Since Pluto did not meet the third criterion, it was downgraded to a dwarf planet.

Now, a group of NASA scientists not only want to restore Pluto’s original status but also reclassify over 100 celestial bodies, including our moon, as planets. The team, led by John Hopkins researcher Kirby Runyon, believes that a planet should be defined by the intrinsic qualities of the celestial body itself, not the external surroundings like its orbit or other objects. They argue that any object in our solar system that hasn’t undergone nuclear fusion and has enough gravitational pull to maintain a round shape, should be called a planet. Under this new definition everything, except for stars, black holes, asteroids, and meteorites, would be considered a planet. This means the number of planets in our solar system would expand from the current eight to almost 110! Among them would be Pluto, our moon, and all newly discovered worlds that are currently dubbed exoplanets.

Pluto (lower right) and, its moon, Charon (upper left) may soon be planets

Though that may sound a lot, especially for students who have to memorize their names, Runyon believes calling them planets will elevate the prestige of the celestial bodies and stimulate the public’s interest. This curiosity will lead to more exploration of our solar system. Additionally, given that most planetary scientists are closely affiliated with geology and other geosciences, the new definition is more relevant than the IAU’s astronomical definition.

While the idea seems valid, the researchers, who presented their arguments at the 48th Lunar and Planetary Science Conference held in Texas from March 20 to 24, still have to obtain approval from the IAU when it meets in Vienna in 2018. Until then, you will have to be satisfied with just eight planets!

Resources: Science Daily,,,

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  • firedog4578
    firedog4578Thursday, February 25, 2021 at 8:52 pm
    Poor pluto
    • BoiWednesday, September 4, 2019 at 8:42 am
      Kinda creeped out by that
      • ASHLEIFriday, May 3, 2019 at 8:09 am
        LOVE VENUS
        • kensleyWednesday, November 7, 2018 at 6:03 am
          it has blood on the planet ahhhhhhh
          • firedog4578
            firedog4578Thursday, February 25, 2021 at 8:51 pm
            Wow, I can see that lol
          • XThursday, October 18, 2018 at 4:43 am
            Go Pluto!
            • johnSunday, April 8, 2018 at 8:58 am
              its cool
              • neena123
                neena123Monday, April 23, 2018 at 12:38 pm
                yeah its so much helpful and has a lot of helpful information!!!!!!:)
              • themTuesday, March 6, 2018 at 10:34 am
                Sounds okay but i'm not all for it (we have to memorize these) :( leave a like if you agree. :)
                • litTuesday, March 6, 2018 at 10:31 am
                  best teax ever
                  • hiTuesday, March 6, 2018 at 10:31 am
                    • Death star Tuesday, March 6, 2018 at 10:25 am